I would not try to make the note convey any one song, only the essence of music. In that end you will need different types of notes, perhaps even overlapping some to convey rhythm, and I would not worry so much about which end of the keyboard, but where on the composition you want to place the notes to balance out the body of the musician. Or will the notes be over the whole background or foreground? I think composition is your main consideration here. So far the quilt is outstanding!